An organic light emitting display (AMOLED) is a hot topic in the present flat panel display research field. Compared with a liquid crystal display, the OLED has advantages of low power consumption, low production cost, self-luminescent, broad viewing angle, and fast response speed and so on. At present, in the display field of a mobile phone, a PDA and a digital camera and the like, OLED has started to replace a traditional LCD display screen. The pixel driving circuit design is a core technical content of the AMOLED display, and has important research significance.
Unlike a thin film transistor liquid crystal display (TFT-LCD) that utilizes a stable voltage to control luminance, OLED belongs to a current-driven display and needs a stable current to control light emitting.